Method and apparatus for perforating and corrugating metallic ribbon



E. M. LACEY, JR. ETAL 3,307,387 METHOD AND APPARATUS FOR PERFORATINGMarch 7, 1967 AND. CORRUGATING METALLIC RIBBON 5 Sheets-Sheet 2 FiledDec. 11, 1963 FIG.

FIG.

FIG. I2

FIG. l4

INVENTORS, E. M. LACEY, JR. W. F RETHWISH D. S HARDING A TTRNEY E. M.LACEY, JR., ETAL 3,307,387 METHOD AND APPARATUS FOR PERFORATING ANDCORRUGATING METALLIC RIBBON March 7, 1967 5 Sheets-Sheet 5 Fil ed Dec.11, 1963 Q9 wi INVENTORS. E. M. LACEY, JR. W. F. RETHWISH D'. S. HARDINGI i A, 21- ATTORNEY United States Patentv C) 3,307,387 METHOD ANDAPPARATUS FOR PERFORATING AND CORRUGATING METALLIC RIBBON Elbert M.Lacey, Jr., Silver Spring, Nev., and William F. Rethwish, National City,and Dale S. Harding, Chula Vista, Calif., assignors to Rohr Corporation,Chula Vista, Calif., a corporation of California Filed Dec. 11, 1963,Ser. No. 329,744 15 Claims. (Cl. 72-324) This invention relatesgenerally to machines for fab ricating honeycomb core and moreparticularly to a ribbon perforator for a corrugation punch press havingprovision for perforating unformed metallic ribbon preparatory tocorrugating the same for use in the fabrication of honeycomb core. I

In a core fabricating machine such as disclosed in Patent No. 3,079,487,issued to F. H. Rohr for Method and Apparatus for Fabricating HoneycombCore, a corrugated metallic ribbon is folded back and forth upon itselfto form the successive layers of the core. In order to form quality highstrength core in this manner, it is necessary that the corrugations inthe ribbon be precisely formed and coined without introducingappreciable distortion or strain into the ribbon material during thecorrugation process. This is imperative in order that the corrugatedribbon will have the same spacing from node to node such that the nodesof the confronting ribbon layers will be aligned and abutted preparatoryto the resistance welding of the nodes together to form the cells of thecore. As disclosed in the aforesaid patent, wherein provision is madefor programming the corrugated ribbon of successive sections ofdifferent thickness to provide a core of predetermined structuralpattern and density, it is equally important that the corrugationconfiguration and nodal spacing be precisely maintained since theseparameters provide the reference datum in determining points in thefabricated core at which changes in density are to occur in accordancewith the predetermined pattern.

wich panel by brazing metallic skins thereto, it usually is required,moreover, that the cell walls of the honeycomb be perforated so that theinert gas which provides a protective atmosphere during brazing cancirculate freely through the honeycomb structure. a The perforations maybe formed by the dies of the punch press itself, as by punching orblanking the openings in the manner disclosed in the aforesaid patent ofFred H. Rohr, but this arrangement is not entirely satisfactory inservice for the In the fabrication of the honeycomb core into a sand- 5reason that the blanks accumulate, are difficult to dispose of, and inmany instances tend to find a way into and between the corrugating diesto thus obstruct the corrugation process.

Perforating the ribbon as by piercing or impaling the same as with aneedle-like device is preferred to blanking, but this method heretoforehas had the disadvantage of introducing incipient tearing, cracking, andfracturing of the ribbon material, which initial effect may be insidiousand, in time, be the cause of a disastrous failure in flight. Thepierced ribbon material has also been found to,be objectionableheretofore for the reason that the resulting protuberances in the ribboncorrugations have prevented free movement of the perforated ribbonthrough the corru-gating dies and have required inordinate undercuttingof the indexing and electrode pins in order to clear the protuberancesas the pins move into and out of the cells of the honeycomb in theprocess of fabricating the core from the corrugated ribbon.

Corrugation punch presses of the type disclosed in the aforesaid patentof Fred H. Rohr provide the required Patented Mar. 7, 1967 coining ofthe metallic ribbon as the corrugations are formed, but have notentirely solved the problem of minimizing the stresses and strains dueto the drawing and in.- ordinate workingof the ribbon as thecorrugations are formed. Even where, as in the aforesaid case, stages ofspring loaded corrugation punches are used in the operation so that thecorrugations are formed only one at a time by the spring loaded dies,the continuous and extensive drawing of the ribbon in the formation ofeach corrugation prohibits the use of pierced ribbon perforations sincethe protuberances cannot slide over the confrontliDng die teeth duringthis drawing movement of the rib- A corrugation punch press suitable foruse in corrugating ribbon which has been pierced to form perforationstherein in. accordance with the perforating process of the presentinvention, is disclosed and claimed in the copending application ofWilliam F. Rethwish and Dale S. Harding for Corrugation Punch Press,Serial No. 314,- 191, fiied October 7, 1963. In accordance with thearrangement of this. preferred form of corrugation press, upper andlower dies, respectively having differentially spring loaded diemembers, cooperate during the initial closing of the dies to yieldablyclamp and holding a previously formed, substantially V-shaped ribboncorrugation between the spring loaded members and, thereafter, as thedies continue to close, to brake the unformed ribbon therebetlween intwo steps, to thus form the two sidewalls of a new corrugation, as theholding die members bottom in successive order, after which the dies,together and as a unit with their holding die members, forcibly moretogether to coin the newly formed corrugation therebetween. In thisoperation, the braking action involves essentially a translatoryswinging movement of the unformed ribbon portions about certain of thetooth edges of the'dies which act as pivotal points. The result of thisaction-is that the necessary drawing of the ribbon from the storage reelis due essentially to the braking action, and as such, does notinterfere with the desired positioning of the protuberances in whatbecome the sidewalls of the corrugation. 'Working of the ribbonmaterial, such as may occur in the corrugation process, moreover, isheld to a minimum, to thus substantially prevent the introduction ofstresses and strains in to corrugated ribbon. Formed nodal portions ofthe ribbon experience no working of the' metal at all, save for ultimatecoining which is desired; the nodal portions merely being translated, asrequired, in the corrugation process to place the nodes alternately atthe peaks and valleys of the corrugated ribbon.

In using this corrugation press with the pre-pierced ribbonperforations, the same are spaced along the length of the ribbon suchthat the protuberances lie in what become the sidewalls of thecorrugations, as aforementioned. As such, the protuberances lie in theportions of the ribbon which brake in the corrugation process, and

since the drawing of the ribbon is largely incidental to the braking ofthe same, the protuberances readily clear the die teeth and arepositioned for' flattening thereby as the dies close. The flattenedprotuberances form an eyelet which prevent the extension of theincipient tearing due to piercing, and also minimize the undercutting ofthe electrode and indexing pins.

In accordance with the perforator process 'of the present invention, anarray of piercing elements such, for example, as steel phonographneedles are supported on the anvil of the corrugation press and arearranged in rows whichlie transversely of the ribbon path. Each needleextends loosely upwardly from its support on the anvil, and its tipportion is disposed or impaled within a small mass of resilient materialsuch, for example, as

a cylinder of soft -rubber which bears against or near the needlesupport. Each loosely mounted needle, together with its impaled rubbercylinder, is readily removed from the array for repair or replacement.

An elongated pad of resilient material, which may be of the samematerial as used in the cylinders, together with a backup supporttherefor, is also disposed transversely of the ribbon path, but thesemembers are supported by the punch or ram of the corrugation press anddepend therefrom initially in spaced relation to the ribbon such thatthe unformed and unperforated portion of the ribbon feeds freely betweenthe confronting surfaces of the pad and the surface support afforded bythe end faces of the array of the rubber cylinders. Following piercingof the ribbon by the needles, both the resilient backup pad and theresilient cylinders, which become compressed during the piercingoperation, expand as the corrugation dies move toward open position andthus operate to strip the ribbon and its protuberances from the pad aswell as from the needles whose tip portions again become fully impaledwithin their respective cylinders.

An object of the present invention is to provide a new and improvedapparatus and process for perforating and corrugating metallic ribbon.

Another object is to provide a ribbon perforation and corrugationapparatus and process which pierces the ribbon and thereafter corrugatesthe same in such a manner that the protuberances which result frompiercing of the ribbon fall into predetermined positions in thecorrugations formed in the ribbon.

Another object resides in the provision of a ribbon perforating andcorrugating process and apparatus in which protuberances resulting frompiercing of the ribbon are pressed into eyelets between the confrontingcorrugation dies.

Still another object is to provide a ribbon piercing arrangement whichis operable by the corrugation press and pierces the ribbon prior tocorrugating of the same in the corrugation dies.

Yet another object in a ribbon piercing perforator resides in theprovision of novel stripper arrangements for freeing the pierced ribbonand the resulting protuberances thereon from the perforator as thecorrugation dies move to open position.

Still other objects, features, and advantages of the present inventionother than those hereinbefore specifically set forth are inherent in, orare to be implied from the novel combination, construction, andarrangement of parts comprising the best mode thus far devised for carrying out the invention and for practicing the methods thereof. Thismode and a specific embodiment thereof will become more fully apparentas the description proceeds with reference to the accompanying drawingswherein:

FIG. 1 is a view in elevation of the perforator and corrugation press ofthe present invention;

FIG. 2 is a view from the underside of the upper perforator and die ofthe corrugation press as viewed along the line 22 of FIG. 1 and rotated90 counterclockwise from the position of FIG. 1;

1 FIG. 3 is an enlarged perspective view of the lower perforatorassembly shown in FIG. 1;

FIG. 4 is a view in elevation of a needle and support assembly disclosedin FIG. 3;

FIG. 5 is a sectional view taken along the line 5--5 of FIG. 4;

FIGS. 6 to 9 are schematic views showing the successive steps ofperforating a ribbon and forming a per forated ribbon corrugationtherein between the dies of the corrugation press;

FIGS. 10a to c are diagrammatic views illustrating further details ofthe corrugation forming process performed on the perforated ribbon;

FIG. 11 is a detail view disclosing the operation involved in thepiercing of the ribbon;

FIG. 12 is an enlarged view depicting the protuberance formed bypiercing of the ribbon;

. FIG. 13 depicts the eyelet which is formed from the ribbonprotuberance when the same is pressed and coined in the corrugationpress; and

FIG. 14 is a sectional view taken along the line 1414 of FIG. 13.

Referring noW to the drawing for a more complete understanding of theinvention, and first more particularly to FIGS. 1 and 2 thereof, 10 and11 designate fixed and movable die supports which, in practice, may bere ferred to as shoes, but for purposes herein, conveniently may beconsidered as the anvil 10 and the ram or punch 11 of a conventionalpunch press. Support 11 is normally positioned above fixed support 10and is slidably mounted on the upstanding and suitably spacedcylindrical guides 13 and 14 for movement forcibly toward and away fromthe fixed support. For this purpose, guides 13 and 14 are suitablysecured to fixed support 10, and movable support 11 is suitably drivenfrom a power source acting through its coupling member 12. Hubs 15 and16 on support 11 extend the bearing surface afforded thereby on guides13 and 14. Hubs 15 and 16 and guides 13 and 14 are disposedconcentrically with respect to semi-cylindrical lateral extensions 17and 18 of support 11.

A die set comprising dies generally designated 19 and 20, respectively,are suitably secured by means (not shown) to the fixed and movablesupports 10 and 11. Dies 19 and 20 are generally similar, and the samereference characters therefore, will be applied to the same or likeelements of these dies throughout the several views.

Each of dies 19 and 20 comprises a forming die member 23 having onetooth 24, and a relatively movable holding die member 25 having twoteeth 26. Die members 23 and 25 for both dies 19 and 20 are identicaland their opposing teeth 24 and 26 complement each other such that thesame intermesh and the line of engagement between the teeth depicts thecorrugation configuration to be imparted to a metallic ribbon 27interposed therebetween. As may be seen from this configuration, theresulting corrugations in the ribbon are generally V- shaped withflattened surfaces or welding nodes 28 and 29 respectively provided atthe crests and valleys of the corrugated ribbon.

Each forming die member 23 is suitably secured at the ends thereof to apair of end plates 31, FIG. 2, which, in turn, are suitably secured tothe die guide block and mounting member 33. Each member 33 has amounting flange 34for mounting its die 19 or 20, as the case may be, onits respective support 10 or 11, as aforementioned. End plates 31 alsohave fastening means (not shown) which serve further for this purpose.

Die members 23, 31 and 33 when asembled and secured together, asaforedescribed, provide a guide channel 35 for the holding die member 25which is provided with a flange or shoulder 36. Guide channel 35 isappropriately widened at 37 to accommodate the shoulder and also toprovide a seat therefor to limit the movement of holding die member 25forwardly or outwardly with respect to the forming or corrugating diemember 23. It will be noted that the widened channel 37 has a greaterlength than that of the shoulder thereby to permit limited relativemovement between the die members Band 25. Thus, when each die 19, 20 ismounted in position on its respective support 10, 11, die member 25 foreach die is limited in its movement in the opposite direction as theshoulder engages the mounting surface of its associated support, as maybe seen in FIG. 1 wherein the dies 19 and 20 are shown to be closed andthe die members 25, insuch case, are properly shown to be bottomed ontheir respective supports. When die members 25 are thus bottomed, theyeffectively become a unit with their respective corrugator die members23, and teeth 26 of each member 25 effectively act as a unitarystructure with their as:

sociated tooth 24. This is important in the precision forming ofcorrugations in metallic materials such as stainless steels wherein itis desired to coin the formed corrugations in the final blow impartedthereto by the punch press in the instant of closing of the dies on theribbon 27 interposed therebetween.

Holding die members 25, as may be seen in FIG. 1, are spring loaded asby coil springs 38, so as to be normally extended yieldably outwardly orforwardly of their respective forming die members 23, these membersbeing sufiiciently elongated, as required, to corrugate ribbons ofvarious widths. A plurality of springs are employed for each die member,and a socket 39 is provided therein for seating each spring 38.Similarly, supports and 11, are provided with sockets 40 which alsoserve to seat the springs, sockets 40 being aligned with andcomplementing the sockets 39 of the die members 25.

For reasons which will become more fully apparent as the descriptionproceeds, die members 25 are differentially spring loaded, the springloading of die member 25 of die 19 being made greater than that ofmember 25 of die as by using two, for example, more springs 38 for diemember of die 19, than for member 25 of die 20. It will be understoodthat whereas differential spring loading has been particularly disclosedherein, the differential bias and'yieldable urging of the holding diemembers 25 may be accomplished by other means such, for example, as byusing air pressure.

The corrugations formed in ribbon 27 are stretched and elongated in acontrolled amount, by stretcher members 47 and 48 of which member 47serves as an anvil and is suitably secured to support 10. Member 48 issecured to and depends from support 11 as by the stud bolts 49 and isadjusted in position therefrom by the nuts 50. For reasons believedinherent in the coining of the corrugations in the punch pressoperation, the resultant spacing between nodes invariably is less thanthat of the die dimensions. The adjustably mounted member 48 is elevatedor lowered at either or both ends relative to support 11, as required,to provide such spaced relation with respect to member 47 as willflatten and thereby stretch the corrugated ribbon sufficiently tocompensate for the under-dimension forming of the spacing between nodesof the corrugations. In some instances, where the corrugation spacingtends to be greater at one side of the ribbon than on the other withresultant tapering of the corrugations over the width of the ribbon,this may be obviated by slightly raising or lowering one end of member48 more or less than the other end relative to the set screws 50individual thereto.

Means for perforating ribbon 27 preparatory to forming and coining thecorrugations therein is generally disclosed in FIG. 1, and comprises alower ribbon piercing assembly, generally designated 51, and an upperback up plate assembly, generally designated 52, which assemblies lietransversely of the ribbon path in confronting relation to each otherand to ribbon 27 disposed therebetween. Assembly 51 is suitablysupported on and secured to a block 53 which, in turn, is suitablysupported on and secured to press support 10.

Back up plate assembly 52 comprises an elongated, relatively massivemetal bar 54 which prefearbly is of square cross section and depended atthe ends thereof from movable press support or ram 11 as by the studbolts 55 which are suitably secured, as by the nuts 57, to the support11 and bar 54, respectively. A resilient ribbon stripper or shedderstrip 58 is suitably secured at the ends thereof to bar 54, as by-screws59. Strip 58 may be formed of any material suitable'for the purposesuch, for example, as sheet rubber (Duro 65).

Referring now more particularly to FIGS. 3 to 5, it will be seen thatthe ribbon piercing assembly 51 comprises a channel member 60 having abase 61 and side walls 62 which are reduced as at 63 in the end regionsof channel member 60 to accommodate bifurcated adjusting 6 plates 64which are releasably secured to base 61 as by the screws 65.

Channel sidewalls 62 and plates 64 form a shallow socket 66 forretaining the needle mounting and supporting members 67, the plates 64being slidably adjusted in the channel, as required, to position andclamp the members'67 therebetwe-en. As may best be seen in FIGS. 4 and5, each of members 67 is apertured transversely thereof to provide aplurality of openings 68 which taken together constitute a commonbottoming plane for a plurality of needles 69. The needles are looselyreceived in openings 70 which are arranged to intersect respectivelywith the openings 68.

Needles 69 per se are essentially rod-like, being pointed at one end andflat at the other; and viewed as an array, are of uniform length. Theneedles may be of any configuration and formed of any material suitablefor the purpose. For example, the needles may be commercially availableDuotone filter point phonograph needles. Each needle 69 is impaled inthe region of its tip portion 71 within a small resilient mass 72,preferably of cylindrical configuration, as shown, the cylinders beingpositioned at or near the upper surface 73 of each of members 67.Cylinders 72 may be formed of any material suitable for the purposesuch, for example, as by being punched from soft sheet rubber (Dur-o 65Referring again to FIG. 3, it will'be seen that the cylinders 72, andhence the needles 69, are spaced along the lengths of members 67 inaccordance with the perforation pattern desired across the width of theribbon, it being noted that the arrangement is such that the needles ofone member 67 are staggered with respect to those of the other to avoidweakening of the ultimate honeycomb structure in its length dimension.In order to space the perforations in the ribbon so as to fall in thesidewalls of the successive corrugations, needle support members 67 arespaced between sidewalls 62 by a plurality of shims 74 and a marcelstrip 75. Strip 75 is interposed between one of the sidewalls and one ofmembers 67 and yieldably urges the same toward the other sidewall. Theshims are interposedbetween this last named sidewall and the other ofthe needle support members 67 and also between the members themselves,as may be seen in the disclosed arrangement of FIG. 3.

Attention is now directed to FIGS. 6 to 14 for a description of theribbon piercing and corrugating operation from which it will become morefully apparent how the essentially braking action of the corrugationpress lends itself to the forming and coining of corrugations in aribbon which has been pierced and protuberated.

With the parts positioned as disclosed in FIG. 6, the punch press isabout to begin a new cycle of operations in which it will pierce a newdouble row of protuberances 56 and form a new corrugation in ribbon 27,the ribbon having been just previously advanced one corrugation bysliding over the rubber cylinders 72,.out of and over teeth 26 of thelower holding die member 25, and thence over anvil 47 of the stretch-outdevice. The ribbon preferably is advanced relative to the perforator,dies, and stretch-out as aforedescribed, by a hitch feed mechanism suchas disclosed and claimed in the copending application of Elbert M.Lacey, Jr., for Method and Apparatus for Feeding Metal Strips, SerialNo. 78,720, filed December 27, 1960, which application also disclosesthe stretchout operation on the corrugated ribbon.

With the previously formed corrugation of ribbon 27 thus seated on thelower die member 25, the opposing member 25 first engages the ribbonduring the initial closing of die 20 toward die 19, the ribbon thenbeing clamped yieldably between the upper and lower ribbon holdingmembers 25, as depicted in FIG. 7, at which time the forming of thefirst portion of a new corrugation is about to begin. As die 20continues to move toward die 19, the same moves relative to its holdingdie member 25 which cannot move at this time because of the greaterspring force acting on the lower holder member 25 which does not moveuntil after the upper die member 25 has bottomed on support 11.

During this relative movement of die member 23 with respect to itsholding die member 25, a first unformed portion 41, FIG. 7, of ribbon27, corresponding to one side of a new corrugation, is formed betweentooth 24 of die 20 and confronting tooth 26 of die 19 as the dies takethe position as shown in FIG. 8.

Members 23 and 25 of die 20 now move as a. unit to thus move holdingmember 25 of die 19 yieldably against its opposing spring force untilthe same bottoms on support 10, as diclosed in FIG. 9. During thismovement, a second unformed portion 42, FIG. 8, of ribbon 27,corresponding to the remaining sidewall of the new corrugation, isformed between the confronting teeth 24 of the opposing corrugating diemembers 23. In the position of FIG. 9, both die members 25 beingbottomed, the newly formed corrugation is coined in the instant offorcible closing of die 20 on die 19.

Shortly after the dies proceed to close further from the position ofFIG. 8, as aforedescribed, shedder strip 58, FIG. 6, moves to engageribbon 27, and on further closing of the dies, strip 58 compressessomewhat as the same moves the ribbon to compress the rubber cylders 72.As this action progresses, of course, the needles 69 further pierce thecylinders and then pierce the ribbon to form the protuberances 56 and,thence, proceed to penetrate somewhat into strip 58, as depicted in FIG.11.

When the dies separate and move to open position, the compressedcylinders 72 expand and, in so doing, lift the perforated ribbon withrespect to the needles 69 to thus retract the needles therefrom. Theneedles, of course, return to their partially impaled positions withinthe cylinders. The compressed shedder strip 58 likewise expands as thesame moves with support 11 to pull away from the compressed cylinders 72and, as this expansion of strip 58 occurs, the ribbon and itsprotuberances 56 are stripped from the shedder strip 58 and thus do notfollow the continued upward movement of the strip to the open positionof the dies, as depicted in FIG. 6.

Referring now more particularly to FIGS. 12 to 14, it will be seen thateach of the protuberances 56 comprises a ring of more or less uniformpeaks 76 distributed about the circumference of each perforation openingformed in the pierced ribbon 27. As otherwise expressed, the initiallyruptured ribbon apparently proc-eeds to tear along uniformly spacedlines as the perforation is enlarged by the progressive penetration ofthe tapered needle into the pierced ribbon. These protuberance peaksdouble back upon themselves during the corrugation process to form aneyelet or more or less symmetrical ring 77 about the perforationopening, as disclosed in FIGS. 13 and 14, and this ring 77 preventsfurther tearing of the ribbon and thus avoids an extension of theincipient tearing of the ribbon which occurs as an icidence of theribbon perforation.

Referring now more particularly to FIGS. a to c, for a more detaileddiscussion of the metal working aspects involved in the forming of a newcorrugation from the perforated ribbon 27, it will be seen that theperforated ribbon portion 41, which has a length A corresponding to thesidewall of the corrugations to be formed, bears critically at P1 ontooth 26 of holding die member 25 of die 19, and also bears criticallyat P2 on tooth 24 of forming die member 23 of die 20. As the dies closeand the forming occurs, ribbon portion 41 brakes about the point P1 inresponse to pressure applied at the point P2. It will be appreciatedthat the ribbon slides for a small distance over the point P2 of tooth24 until the same reaches the position of FIG. 10b. In the brakingaction of the unformed ribbon portion 41, the end of the same followsthe circular path about point P1 indicated by the dashed line 43. Thatdiminishing portion of the unformed ribbon lying between this dashedline and point P2, of course, experiences a combined sliding and brakingmovement over point P2. While a purely braking action would be ideal, noadverse effects are manifested. The protuberance 56 in ribbon portion 41is thus simply moved in a swinging motion to a position against thesidewall of tooth 26 of die member 25 of die 19 preparatory to beingflattened thereagainst by the approaching surface of tooth 24 of diemember 23 of die 20.

A second unformed ribbon portion 42, also having a length A and aprotuberance 56, bnakes about the point P3 on tooth 24 of die member 23of die 20, as die member 25 of die 19 moves to bottom on support 10, anda combined sliding and braking action of the ribbon occurs about thepoint P4. The braking action of unformed ribbon portion 42 about pointP3 thus is such that the end of the ribbon portion effectively followsthe circular path indicated by the dashed line 44 shown in FIG. 10b, andthe protuberance 56 in ribbon portion 42 is simply translated in aswinging movement to a gposition against the sidewall of tooth 24 of die20 preparatory to being moved and coined thereby against the confrontingsidewall of tooth 24 of die 19.

That portion of the unformed ribbon, which lies between points P2 andP3, is designated 45 and has the nodal length B. Ribbon portion 45 issimply translated to the base of tooth 24 or die member 23 of die 19 asmember 25 thereof moves to bottom on the die support 10. As a practicalmatter, unformed but coined ribbon portion 45 together with ribbonportion 41, may be considered to be a first unformed ribbon portion, inthe same sense that the corresponding unformed but coined ribbon portion46, FIG. 100, which lies between the points P4 and P5 at the closing ofthe dies, together with ribbon portion 42, may be considered to be aremaining ribbon portion, required to form a new complete corrugation,which will thus be made up of ribbon portions 41, 45, 42 and 46, as maybest be seen in FIG. 100. Although the corrugation width, i.e., asmeasured from node to node, may be seen to be B plus D, a length ofribbon corresponding to 2B plus 2A is required to form the newcorrugation. Of this length, as has been described, there is no workingof the B portions; only coining. D minus B, of course, does not equal2A, since purely braking does not occur in the forming of the Aportions; but this is substantially the case, and the ultimate coiningof the formed ribbon in the region of points P2 and P4 removes anyadverse effects which may have been introduced in the previous workingof the material as it slides over the teeth at these points. In effect,the substantial length of each A portion and the protuberance thereon issimply translated in a swinging movement of the unformed ribbon portionabout the edge of one of the die teeth.

The results of the combined perforation and corrugation process asaforedescribed are, first, precision forming of the perforated ribboncorrugations and, second, high quality blocks of honeycomb core free ofincipient tear conditions when the blocksare fabricated from theperforated and precision corrugated ribbon. Such blocks are undistortedand unwarped and have optimum welds at abutting nodes which are alignedconsistently from node to node. The fabrication of cores from suchribbon desirably may be programmed with assurance that the corrugationwill be of uniform spacing and the nodes will properly align and abutpreparatory to welding of the same together. The cores, moreover, havingthe perforated cell walls may readily be fabricated into sandwichstructures in any brazing process requiring the circulation through thecore of a protective gaseous atmosphere.

It will be apparent from the foregoing that a perforation andcorrugation press and process has been provided 9 which is well adaptedto fulfill the aforestated objects of the invention. It will beapparent, moreover, that this invention may be embodied in other formsor carried out in other ways without departing from the spirit oressential characteristics thereof. The present embodiment of theinvention is therefore to be considered as in all respects illustrativeand not restrictive, the scope of the invention being indicated by theappended claims, and all changes which come within the meaning and rangeof equivalency of the claims are intended to be embraced therein.

Having thus described our invention, what we claim as new and useful anddesire to secure by Letters Patent is:

1. Themethod of perforating and corrugating metallic ribbon to formsubstantially V-shaped perforated corrugations therein having nodalportions at the crests and valleys which comprises the steps of piercingthe ribbon, and concurrently corrugating eyeleting and coining thepierced ribbon so that the protuberances resulting from the piercing ofthe same fall into predetermined po sitions in the sidewalls of thecorrugations, and the protuberances become eyelets in the coining ofsaid sidewalls.

2. The method as in claim 1 and further comprising the step ofstretching the corrugated ribbon to set the nodal spacing ofthe-corrugations at a predetermined value.

3. The method of perforating and corrugating metallic ribbon to formsubstantially V-shaped corrugations having perforated sidewalls andnodal portions at the crests and valleys, comprising the steps ofpiercing the ribbon to form protuberan-ces therein spaced along thelength thereof, braking successive portions of the pierced ribbon tocorrugate the same such that said protuberances fall respectively in thesidewalls of the corrugations, coining the corrugations and transformingsaid protuberances therein to eyelets, and stretching the corrugatedribbon to set the nodal spacing of the corrugations at a predeterminedvalue.

4. The method of perforating and corrugating metallic ribbon to formsubstantially V-shaped corrugations therein having perforated sidewallsand nodal portions at the crests and valleys, comprising the steps ofadvancing the ribbon intermittently longitudinally of the same, piercingthe ribbon as the same advances to form protuberances therein spacedalong thelength thereof, braking successive portions of the piercedribbon to form said V-shaped corrugations therein such that saidprotuberances fall respectively in the sidewalls of the corrugations,coining the formed corrugations and eyeleting said protuberancestherein, and flattening the corrugated ribbon to stretch the same andset the nodal spacing of the corrugations at a predetermined value.

5. The process as in claim 4 and wherein said piercing, corrugating,coining, eyeleting, and flattening of the ribbon occur concurrentlyduring intervals between the intermittent advances of the ribbon.

6. A system of perforating and corrugating metallic ribbon to formV-shaped corrugations having perforated sidewalls comprising, incombination, means for piercing the ribbon transversely thereof andrecurrently at predetermined spaced intervals along the length of theribbon as the same is intermittently advanced longitudinally, and meansoperated concurrently with the piercing means for concurrently braking,eyeleting and coining the pierced ribbon to corrugate the same such thatthe resultant perfo rations in the ribbon fall in the sidewalls of thecorrugations and become eyeletted as the corrugations are formed.

7. The system as in claim 6 and further comprising means operatedconcurrently with the piercing and corrugating means for stretching theformed corrugations.

8. Apparatus for perforating and corrugating metallic ribbon comprising,in combination, relatively movable and stationary members disposed forintermittent passage of a metallic ribbon therebetween longitudinally ofthe ribbon, die means respectively supported by said members for brakingand corrugating the ribbon as the members close relatively toward eachother, ribbon piercing means respectively supported by said members anddisposed in advance of the corrugating means along the line of ribbonmovement for forming perforations and resultant protuberances in theribbon as the members close relatively toward each other, andcorrugation stretcher means sup ported respectively by said members anddisposed behind the corrugating means along the line of ribbon movementfor flattening the formed corrugations thereby to stretch the same apredetermined amount as the members close relatively toward each other.

9. Apparatus as in claim 8, said ribbon piercing means comprising aplurality of sharpened ribbon piercing elements disposed in spacedrelation in a row transversely of the ribbon and supported on thestationary member with their sharpened ends extended upwardly, aplurality of small masses of resilient ribbon stripping material impaledrespectively on said ribbon piercing elements, an elongated back upplate supported by the movable member and aligned in opposed relation tosaid row of piercing elements, and a strip of resilient ribbon strippingmaterial secured to said plate in confronting relation to said sharpened elements, said resilient strip serving to strip the pierced ribbonand its resultant protuberances from the strip and said small resilientmasses serving to strip the pierced ribbon from said piercing elementsas the fixed and movable members relatively separate following piercingof the ribbon by said piercing elements during relative closing of themembers toward each other.

10. Apparatus as in claim 9, said ribbon piercing means comprising tworows of said ribbon piercing elements, the elements of one row beingstaggered with respect to the elements of the other row.

11. Apparatus for perforating metallic ribbon comprising, incombination, relative movable and stationary members disposed forintermittent passage of a metallic ribbon therebetween longitudinally ofthe ribbon, a plurality of sharpened ribbon piercing elements disposedin spaced relation in a row extended transversely of the ribbon andsupported loosely and removably on the stationary member with theirsharpened ends extended upwardly, a plurality of small masses ofresilient ribbon stripping material impaled respectively on said ribbonpiercing elements such that each of said masses of stripping materialand its associated ribbon piercing element forms a removable unit, anelongated back up plate supported by the movable member and aligned inopposed relationto said row of piercing elements, and a strip ofresilient ribbon stripping material secured to said plate in confrontingrelation to said row of sharpened elements.

12. Apparatus as in claim 11, and further comprising two rows of saidribbon piercing elements and means for supporting the elements on saidstationary member, said means comprising an elongated retainer plate foreach row of elements, each said retainer plate having a plurality ofopenings respectively receiving said elements loosely therein, each ofsaid plurality of openings having a transversely intersecting openingdefining a bottom support surface for its respective element, achanneled support for said retainer plates, spacer means for varying thespaced relation of said retainer plates within said channeled support,spring means for yield ably retaining the retainer plates in adjustedspaced relation within the channeled support, means for adjustablyspacing and securing the retaining plates longitudinally of the channelsupport, and means for securing the channeled support to the stationarymember.

13. Apparatus as in claim 11, and further comprising two rows ofsaidribbon piercing elements, the elements of one row being staggeredwith respect to the elements of the other row.

14. Apparatus as in claim 11, said ribbon piercing elements comprisingconventional phonograph needles.

References Cited by the Examiner UNITED STATES PATENTS 1,573,810 2/1926Cunningham 72384 2,403,035 7/1946 WVhitson 83-l39 2,413,179 12/1946Grandmont et a1. 72-404 1/1950 Urquhart 83139 1/1955 Lubeck 72-325FOREIGN PATENTS 2/1934 France. 4/1942 Great Britain.

CHARLES W. LANHAM, Primary Examiner.

L. A. LARSON, Assistant Examiner.

1. THE METHOD OF PERFORATING AND CORRUGATING METALLIC RIBBON TO FORMSUBSTANTIALLY V-SHAPED PERFORATED CORRUGATIONS THEREIN HAVING NODALPORTIONS AT THE CRESTS AND VALLEYS WHICH COMPRISES THE STEPS OF PIERCINGTHE RIBBON, AND CONCURRENTLY CORRUGATING EYELETING AND COINING THEPIERCED RIBBON SO THAT THE PROTUBERANCES RESULTING